Page 67 - Design for Six Sigma a Roadmap for Product Development

44 Chapter Two

2.5.4 Quick setup time reduction
When one-piece flow and the cellular manufacturing system are used,
it is very important that the setup time needed from producing one
type of product to another type of product should be greatly reduced.
Otherwise, the production system will be overwhelmed by frequent
and long changeover times from one type of production to the next.
The Toyota production system developed many quick setup time
reduction techniques. However, the key idea is to divide the setup time
into two categories of elements: internal elements and external ele-
ments. The internal elements are the actions needed in the setup
where the regular production has to stop. The external elements are
the actions needed in the setup where the regular production does not
have to stop. The key strategy in quick setup time reduction tech-
niques is to redesign the work elements in setup so that an over-
whelming amount of setup work is done externally, that is, without
production stoppage.
In service industry, there might be at least a thousand-year history
of using quick setup time reduction techniques in the restaurant
industry. One of the keys for success in the restaurant business is to
reduce the production lead time, that is, the time from customer order
to the time the customer is served with food. Nobody wants to wait in
a restaurant for hours without food. The kitchen has to be able to
switch over from one item to another without much delay. The setup
time for different dishes must be very fast; it is impossible to “batch
produce” the same dishes and save those as inventory, and one-piece
flow should be strictly enforced. People in the restaurant kitchen
found numerous ways to do the quick changeover. The main trick is to
do a lot of preparations “off line,” that is, when there is no customer
order or in parallel to the cooking process. This is the same idea as that
of the Toyota production system.

2.5.5 Pull-based production
A pull-based production system means a demand-driven production
system. The pull-based production system is modeled after the super-
market shelf replenishment operation. In the supermarket shelf, there
are lots of goods, such as milk, eggs, and orange juice that are ready
for customers to pick up. The customers “pull” the goods from the
shelf, then depending on how many items are taken away, the inven-
tory person in the supermarket will “refill” the same amount of items
by pulling them from the warehouse, and finally the warehouse person
will order roughly the same amount of items that are pulled from
warehouse.